The present invention relates generally to medical instrumentation and in particular, to apparatus and methods which support a wide variety of measurement, collection, communication, and analysis functions.
There exists a need for comprehensive physiological monitoring in portable and remote settings. Current systems are generally large, costly, and inflexible, and although portable devices are now becoming available, they provide only limited, special-purpose capabilities. More specifically, existing medical instruments do not support multiple, programmable input channels which would allow any analog signal type (EEG, EMG, EKG, or hiaher-level signals) to be filtered amplified, digitized, encapsulated, and routed through a complex digital network under programmed control, thereby offering a truly universal data core function.
At the same time, in the computer industry there has been a movement toward system interoperability through open systems protocols. This movement is being driven by TCP/IP, followed by X-windows (for transmission of windowed graphics), NFS (for file systems access), and new applications level protocols and file formats such as X.500. HTML. and SMTP. These protocols and file format standards have allowed interoperability between computers using different operating systems, hardware platforms, and applications suites. Within the Government and industry these data transfer protocols, mostly oriented towards transmission and/or sharing of images and documents, have substantially improved the usefulness of office and home computers. With respect to medical instrumentation, however, such support for multiple platforms or distributed, object-oriented collection and analysis architectures for multiple data types do not yet exist.
To review relevant patent literature, U.S. Pat. No. 4,838,275 describes a home medical surveillance system which is designed to serve multiple patients in their homes. The system suggests the sensing of multiple parameters for patient health assessment and which are sent to a central observation sight. The data transmission/reception methods described predate the widespread use of the modern, distributed Internet concepts, and instead rely on simple point-to-point data transfer without specific data-independent object-oriented encapsulation coding methods. Data interpretation is strictly manually performed by a human observer, with no means for automated signal interpretation, and there is no indication that the input channels for data are in any sense general purpose.
U.S. Pat. No. 5,228,450 describes apparatus for ambulatory physiological monitoring which includes compact portable computer controlled data acquisition of ECG signals, including buffering and display. The invention focuses on the collection of ECG data and does not describe how any other physiological signal might be acquired. Nor does the invention include a communications means or an architecture in support of propagation encapsulated object-oriented data.
U.S. Pat. No. 5,231,990 describes an applications-specific integrated circuit for physiological monitoring which supports multiple inputs to implement flexible multi-channel medical instrumentation. The signal processing and programmable gain functions described are consistent with ECG-type filtering and monitoring. However, the subject matter does not involve communications or network interoperation data buffering, data encapsulation, or an architecture for routing, buffering, and analysis. While the invention does involve programmable functions, it does not describe how it could be applicable to all relevant medical signals (specifically EEG).
U.S. Pat. No. 5,331,549 describes a medical monitoring system which supports a plurality of vital signs measurements supplied on a continuous basis to a central data collection server, which in turn, provides various display functions. The invention does not indicate that the vital signs inputs are multiple function, that the central computer is networked to other systems so that data collection and viewing can occur anywhere in the network, or that data is in anyway encapsulated for object-oriented processing.
U.S. Pat. No. 5,375,604 describes a transportable modular patient monitor which supports the collection of data from a plurality of sensors. The system supports multiple types of data through attachable applications-specific pods which have the electrical characteristics necessary to match specific low-gain sensor input signals (EKG, blood pressure, pulse oximetry, etc., but not EEG). The system transfers data to and from the patient and display systems through a local area network connection. Key innovations appear to be modular signal specific data collection pods, detached portable monitoring system with docking stations, and a means for providing continuous monitoring. The patent does not describe input channels which, under programmed control, are configurable to all medical sensor inputs, nor does it describe a local and wide area network data collection, encapsulation, routing, or analysis.
U.S. Pat. No. 5,458,123 measures vital signs sensors and uses a multiple antenna-based radio direction finding system for tracking patient location. The system is restricted to low-gain physiological signals such as EKG, temperature, heart rate, etc.
U.S. Pat. No. 5,438,607 describes a programmable monitoring system and method for use in the home, medical ward, office, or other localized area. A particular pulse-coded RF signal coding system transmits calls for emergency service to a home/office receiver which in turn, is routed through telephone network to a central monitoring office. The invention involves wireless transmission and routing from a single point to point, but does not involve collection of physiological data nor the transmission, buffering, or analysis of such information.
U.S. Pat. No. 5,549,117 describes a system for monitoring and reporting medical measurements which collect data on a remote stand-alone monitoring system into a relational database. The remote unit provides a means for generating reports and transmitting them to a health care provider. The disclosure is principally directed toward respiratory function sensors.
U.S. Pat. No. 5,558,638 describes a system for monitoring the health and medical requirements of a plurality of patients using a base unit located at each patient to connect to a number of sensors and/or recorders. The base unit stores the data which is transferred to a care center which analyses the data. The care center can also communicate with the base unit through a local area network. No evidence is given for hardware support for EEG or other vital signs measurements from a general purposed programmable analog input system, nor is a method for data encapsulation described.
U.S. Pat. No. 5,590,648 describes a personal heath care system which supports a plurality of patient monitoring sensor modules, but does not support multi-function analog inputs. A data processor with data communications modem is described but not a wide/local area network connections coupled to a distributed encapsulated data collection, buffering, routing, and analysis system. Means are not provided enabling one or multiple patients to be monitored by one of many monitoring stations.
The subject invention satisfies the need for a general-purpose, low-cost system which provides comprehensive physiological data collection, with extensive data object oriented programmability and configurability for a variety of medical as well as other analog data collection applications. In a preferred embodiment, programmable input signal acquisition and processing circuits are used so that virtually any analog and/or medical signal can be digitized from a common point of contact to a plurality of sensors. A general-purpose data routing and encapsulation architecture supports input tagging and standarized routing through modern packet switch networks, including the Internet; from one of multiple points of origin or patients, to one or multiple points of data analysis for physician review. The preferred architecture further supports multiple-site data buffering for redundancy and reliability, and real-time data collection, routing, and viewing (or slower than real-time processes when communications infrastructure is slower than the data collection rate). Routing and viewing stations allow for the insertion of automated analysis routines to aid in data encoding, analysis, viewing, and diagnosis.